I recommend you to make a copy of this file if you want to restore the behavior for showing password. And this is the recommended way when you are deleting files from your system. Back up can be done by:

sudo cp /etc/sudoers.d/0pwfeedback ~/Downloads/

And then you can delete the file. Later if you want to restore it you can run:

sudo cp ~/Downloads/0pwfeedback /etc/sudoers.d/

Restore the '*' behavior

The file content is simple one so you can simply recreate the file with this content: